This invention relates to collagen and more particularly to regenerated soluble collagen fiber.
"Natural insoluble collagen" as used herein means and refers to collagen which cannot be dissolved in an aqueous alkaline or in any inorganic salt solution without chemical modification and includes hides, splits and other mammalian or reptilian coverings. More particularly "natural insoluble collagen" means and refers to the corium which is the intermediate layer of a bovine hide between the grain and the flesh sides.
Collagen constitutes the connective tissue and is the major type of fibrous protein in higher vertebrae. Collagen in its natural state exists in a triple chain helix along with the constant periodicity between aligned triple chains. The triple chain helical configuration of collagen is sometimes referred to as a fibril and the fibrils align with an axial periodicity of about 640 A.
Although there are several types of collagen, the major type is referred to as "Type 1" which is the major collagen of skin, bones and tendons. The Type 1 collagen has a chain composition of [.alpha.1(I).sub.2 .alpha.2]. The .alpha.1(I) and .alpha.2 chains are homologous.
In young animals there is little intramolecular and intrafibular crosslinking which provides for some degree of solubility of the collagen. However, during the aging process both intramolecular and intrafibular crosslinkings occur thus making the collagen insoluble.
Collagen and products derived therefrom have utility in the food, cosmetic and pharmaceutical fields. While it is known that collagen can be purified by the depolymerization of natural and soluble collagen along with subsequent reconstitution, the yields have been somewhat low and the resultant product is not always uniform.
U.S. Pat. No. 3,637,642 is exemplary of a process for dissolving insoluble collagen and regenerating the fiber.
Further, methods have been proposed for solubilizing and reconstituting collagen with the use of enzymes to sever intra- and interfibular bonds such as is disclosed in U.S. Pat. No. 3,034,852. Further, processes have been proposed for converting collagen fibrous masses to sheet-like material such as in U.S. Pat. Nos. 2,934,447 and 2,934,446.
Many processes of the prior art require that the treatment be conducted on the corium of the hide which is the collagen-rich source. To obtain the corium the hair is normally removed by liming or the like and the flesh containing a substantial amount of fat is normally stripped from the opposing side of the hide.
In accordance with the present invention a method of forming the soluble collagen fiber is provided wherein a raw hide is readily processed from its raw stage to form collagen fibers without complicated processes.